During maturity, the type are characterized usually by a lean body, or tendency rapidly to become thin under stress.  They have clean cut features and thick hair, often wavy or curly, thick long eyebrows, large, frank, brilliant, keen eyes, regular and well developed teeth and mouth.  Sexually they are well differentiated and susceptible.  Noticeable emotivity, a rapidity of perception and volition, impulsiveness, and a tendency to explosive crises of expression are the distinctive psychic traits.  A restless, inexhaustible energy makes them perpetual doers and workers, who get up early in the morning, flit about all day, retire late, and frequently suffer from insomnia, planning in bed what they are to do next day.

Certain types of thyroid excess associated with the thymus dominant next to be described are peculiarly susceptible to emotional instability.  They are subject to brain storms, outbreaks of furious rage, sometimes associated with a state of semi-consciousness.  To emphasize the analogy to epilepsy, their attacks have been called psycholepsy.  Among the Italians especially they were watched and reported during the War, when the explosive fits were seen to take the form of irresponsible acts of insubordination or violence.

THE THYMO-CENTRIC PERSONALITIES

During the first period of childhood, up to five, six or seven, or more accurately, up to the point at which the permanent teeth begin to appear, every child may be said to be a thymus-dominated organism, because the thymus, holding the other endocrines in check, controls its life.  That is why up to the third and fourth years at any rate, most children seem alike.  Closer observation, however, reveals points of differentiation and signs of the coming potencies of the other hormones.  During the second period, up to puberty, these marks of the deeper underlying forces of the personality make themselves more and more felt.  The thymus, like a brake that is becoming worn out, continues to function in a progressively weaker fashion.  Until with the arrival of the gonadal (ovaries’ or testes’) internal secretion, its influence is wiped out.

There is a definite degree of thymus activity during everyone’s childhood, unless by its premature involution, precocity displaces juvenility.  Yet even during childhood, there are certain individuals with excessive thymus action, foreshadowing a continued thymus predominance throughout life.  The “angel child” is the type:  regularly proportioned and perfectly made, like a fine piece of sculpture, with delicately chiselled features, transparent skin changing color easily, long silky hair, with an exceptional grace of movement and an alertness of mind.  They seem the embodiment of beauty, but somehow unfit for the coarse conflicts of life.  In English literature several characters are recognizable as portraits of the type, notably Paul Dombey, whose nurse recognized that he was not for this world.  They may look the picture of health, but they are more liable than any other children to be eliminated by tuberculosis, meningitis or even one of the common diseases of childhood.